Hunting for dark energy with upcoming cosmological surveys

Research Group: 
Astronomy Unit
Number of Students: 
Length of Study in Years: 
Full-time Project: 
QM Scholarship
Project Description: 
During the last few years, we have entered the “golden era” of observational cosmology. The standard cosmological model fits the data extremely well, but requires the existence of two exotic constituents, namely dark energy in the form of a cosmological constant, and cold dark matter. Dark energy currently dominates the Universe and it is responsible for its accelerated expansion.

Our ignorance about the nature of dark energy is arguably the most important issue in cosmology today. Theoretical cosmologists have suggested that dark energy could be a dynamically evolving scalar field, or it could be a manifestation of the laws of gravity changing on large, cosmological scales. That is, Einstein’s General Relativity might not be the correct theory of gravity on all scales.

In the next few years, state-of-the-art cosmological surveys with instruments like the Euclid satellite, the Square Kilometre Array, and the Large Synoptic Survey Telescope, are promising to map the large scale structure of the Universe and pin down the nature of dark energy.

The Astronomy Unit at Queen Mary University of London has access to all these surveys. This PhD project aims to develop tests of dark energy and gravity using these surveys and exploit synergies between them. The student will gain experience in theoretical and observational cosmology, dark energy and modified gravity models, numerical methods, and will be part of a vibrant international community of scientists.

A degree in Physics, Mathematics, or similar.
Some programming experience (e.g. Python or C/C++) is desirable.

SPA Academics: 
Alkistis Pourtsidou
Some specific projects that the PhD could include are: 
  • Using the innovative 21-cm intensity mapping technique, which promises to revolutionize cosmology in the radio wavelength, to study dark energy and modified gravity with the Square Kilometer Array. This would involve developing numerical simulations and data analysis techniques.
  • Exploiting cross-correlations and synergies between radio surveys (e.g. Square Kilometer Array) and optical galaxy surveys (e.g. Euclid, LSST). 
  • Using the Square Kilometer Array to perform precision cosmology studies and very high redshifts (early times) that are inaccessible by optical galaxy surveys and hence currently unexplored!